Watershed and Wallet Friendly Roads

Improving Water Quality While Reducing Maintenance Costs

Storm-proofing road systems can have an immediate benefit to the streams and aquatic habitat as well as protect the road surface and reduce annual road maintenance costs. The practices recommended below help ensure that stream habitat is not impacted by human-related erosion. If storm-proofing treatments are implemented correctly, future storm runoff can cleanse the streams of accumulated coarse and fine sediment rather than deposit fine sediments in areas where it impairs habitat.

Concentrated flow from the road network enters the stream system with greater volume and velocity than what the stream would normall experience. The increased energy of the water causes the stream channel to incise, which may ultimately lead to bank erosion and lowering of the water table

Since roads collect and channel water moving across the surface, less water ends up recharging the groundwater basin, which decreases summertime stream flows and leads to drier soils downhill of the road

Ensure stream crossings have fail-safe features to direct flood waters back into natural stream channel

Before - culvert undersized and placed at shallower angle than stream channel

After - culvert is properly sized, aligned, and culvert outlet is properly rocked to dissipate energy of outflow waters

Before - culvert is undersized and placed at shallower angle than stream channel; culvert is fish passage barrier

After - bridge spans channel so that there is minimal disturbance of road crossing to creek flow and habitat

DECOMMISSION ROADS

If road systems are no longer needed to manage a property, they can be decommissioned such that their impacts are erased from the watershed. Landowners can elect for complete decommissioning, or long term winterization of the roads, which gives them the option to re-establish roads in the future.

Drainage structures, like culverts, and fill material are completely removed

Excavated material from crossing may be relocated to cutbanks to promote vegetation growth or hauled to stable location

BMPs for paved and public roads - Napa County Public Works, Guidelines for County Road Maintenance Practices that Protect Aquatic Habitat and Salmon Fisheries

USDA Low-Volume Roads Engineering BMPs Field Guide - Guidance for road builders, roadmanagers, and resource specialists in most geographic areas to help build better, more cost-effectiveroads, and roads that minimize adverse environmental impacts and protect water quality.